[FFmpeg-user] Need Help For Splitting, Re-Encoding and Joining again

[Gabriel Balaich]

Try using .ts instead of mp4, they seem to segment better, end result can
still
be converted back to .mp4.

1) ffmpeg -i F:\video_data_set\4k_compressed.mp4 -f segment
-segment_time 5 -segment_start_number 1 -codec copy
F:\video_data_set\test\%d_4k_compressed.ts

2) ffmpeg -hide_banner -i F:\video_data_set\test\1_4k_compressed.mp4
-c:a aac -ar 44100 -b:a 128k -c:v libx264 -x264opts nal-hrd=cbr:force-cfr=1
-pix_fmt yuv420p -profile:v baseline -level 3.0 -vf
"scale=1280:-2,setdar=16:9" -b:v 3.9M -minrate 3.9M -maxrate 3.9M -bufsize
7.8M -preset ultrafast -crf 18 -r 30 -g 30 -threads 8 -copyts
F:\video_data_set\test\1_4k_compressed_1.ts

3) ffmpeg -hide_banner -f concat -safe 0 -i
F:\video_data_set\test\files_2.txt
-c copy -threads 8 F:\video_data_set\4k_compressed_1.mp4

On Thu, Mar 29, 2018 at 3:00 AM, Faraz Ahmed <faraz.ahmed at purelogics.net>
wrote:

>  Hi,
>
> We want to encode large video files faster.
> To make encoding faster we are using multiple encoding servers.
> Below is our process of encoding flow
>
>
>    1. First we split the video into small segments using below command
>    2. ffmpeg -i F:\video_data_set\4k_compressed.mp4 -f segment
>    -segment_time 5 -segment_start_number 1 -codec copy -copyts
>    -avoid_negative_ts 1 F:\video_data_set\test\%d_4k_compressed.mp4
>    3. Then we divide these segments among multiple encoding servers
>    4. Each encoding server re-encode the segment using below command
>    5. ffmpeg -hide_banner -i F:\video_data_set\test\1_4k_compressed.mp4
>    -c:a aac -ar 44100 -b:a 128k -c:v libx264 -x264opts
> nal-hrd=cbr:force-cfr=1
>    -pix_fmt yuv420p -profile:v baseline -level 3.0 -vf
>    "scale=1280:-2,setdar=16:9" -b:v 3.9M -minrate 3.9M -maxrate 3.9M
> -bufsize
>    7.8M -preset ultrafast -crf 18 -r 30 -g 30 -threads 8
>    F:\video_data_set\test\1_4k_compressed_1.mp4
>    6. When all segments have re-encoded then we join them to make single
>    file using below command
>    7. ffmpeg -hide_banner -f concat -safe 0 -i
> F:\video_data_set\test\files_2.txt
>    -c copy -threads 8 F:\video_data_set\4k_compressed_1.mp4
>
>
> All is performing well but the issue we are facing is that after each
> segment there is click sound in output audio.
> For example i have encoded 5 segments having duration 6,6,3,6 and 6 seconds
> when i joined them using above mentioned command the output video has click
> sound at 6,12,15 and 21 seconds of video. I am also sharing my output video
> link below.
>
> https://www.dropbox.com/s/2dugqt944n19s2j/4k_compressed_1.mp4?dl=0
>
> Can you please help me and let me know what is the cause of this click
> sound and how to fix and remove this click sound from output video.
>
>
>
> Thanks,
> Faraz
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